The present invention relates generally to a resistance device for use with exercise equipment, and more particularly to resistance units for bicycle trainers.
For many years, bicycle trainers have been used by bicycling enthusiasts to convert their bicycles for stationary riding. Rather than ride in cold or rainy weather, the cyclist can use the trainer to ride indoors and obtain an aerobic, cardiovascular workout. Bicycle trainers also obviate the need for purchasing a separate stationary bicycle for those persons who want to occasionally workout while, for example, reading or watching television. Regardless of the reasons for its use, a bicycle trainer should be easy to use and, to the extent possible, simulate bicycle riding on the open road.
To provide the user with a workout that simulates riding on the open road, a bicycle trainer should be designed with a resistance unit that provides increasing resistance to match the energy output of the rider. Presently, many conventional bicycle trainers do not simulate bicycle riding well because of the design limitations of their resistance units.
A typical bicycle trainer has a frame onto which the user mounts the bicycle. An example of a bicycle training system is described in U.S. Pat. No. 5,611,759. Typically, the rear wheel of the bicycle is contacted with a roller that is, in turn, connected to a resistance unit.
In general, in one aspect, the invention features a resistance applying device for use with an exercise apparatus including a rotatable shaft, a rotatable impeller coupled to the rotatable shaft, a sealed housing surrounding the rotatable impeller, the sealed housing containing a fluid that provides resistance against the rotation of the impeller, and a barrier located between the rotatable impeller and the housing, the barrier and the rotatable impeller being configured to provide for relative movement between the barrier and the rotatable impeller.
Embodiments of the invention may include one or more of the following features. The rotatable impeller can have at least one vane. The barrier can be located between a stationary impeller and the rotatable impeller. The stationary impeller can have at least one vane. The barrier can allow at least a portion of the vane of the stationary impeller to be exposed to the rotatable impeller. The barrier can have a slot through which the vane of the stationary impeller fits. The barrier can be substantially planar. The barrier can be a substantially circular plate. The invention can include a stationary impeller, the barrier being located between the stationary impeller and the rotatable impeller, the rotating and stationary impellers being substantially circular and planar, each with at least one vane on a surface, the surface of the rotating impeller having its respective vane being oriented to face the surface of the stationary impeller having its respective vane. An adjuster can adjust the relative position of the barrier and the rotatable impeller. The adjuster can be a movable resistance indicator accessible by an operator on the exterior of the housing.
In general, in another aspect, the invention features a resistance applying device for use with an exercise apparatus including a rotatable shaft, a rotatable impeller coupled to the rotatable shaft, the rotatable impeller having at least one vane, a fixed impeller facing opposite the rotatable impeller, the fixed impeller having at least one vane facing the rotatable impeller, a sealed housing surrounding the rotatable impeller and the fixed impeller, the sealed housing containing a fluid that provides resistance against the rotation of the impeller, and a barrier located between the rotatable impeller and the fixed impeller, the barrier allowing at least a portion of the vane of the fixed impeller to be exposed to the rotatable impeller.
Embodiments of the invention may include one or more of the following features. The relative position of the barrier and the rotatable impeller can be adjustable. Adjusting the relative position of the barrier and the rotatable impeller can change how much of the vane of the fixed impeller is exposed
In general, in another aspect, the invention features a method for adjusting the resistance of a resistance applying device for use with an exercise apparatus, where the resistance applying device includes a rotatable shaft, a rotatable impeller coupled to the rotatable shaft, and a sealed housing surrounding the rotatable impeller, the sealed housing containing a fluid that provides resistance against the rotation of the impeller, including the steps of turning the rotatable impeller within the fluid within the sealed housing, and adjusting the volume of fluid adjacent to a moving surface of the rotatable impeller.
Embodiments of the invention may include one or more of the following features. The volume of fluid can be adjusted by changing the relative position of a plate and the rotatable impeller. The changing of the relative position can change the distance between the plate and the rotatable impeller. The distance can change along an axis substantially normally to the plate. The rotatable impeller can have at least one vane. A stationary impeller can be located between the rotatable impeller and the sealed housing, and the stationary impeller can have at least one vane. At least a portion of the vane of the stationary impeller can be exposed. A stationary impeller can be located between the plate and the sealed housing, wherein both the rotating and stationary impellers are substantially circular and planar, each with at least one vane on a surface, the surface of the rotating impeller having its respective vane being oriented to face the surface of the stationary impeller having its respective vane. An adjuster can be provided that adjusts the relative positions of the barrier and the rotatable impeller. The adjuster can be a movable resistance indicator accessible by an operator on the exterior of the housing.
Advantages of the invention may include one or more of the following. By varying the volume of resistance fluid adjacent to the rotatable impeller, or by varying the surface area of the vanes of a stationary impeller exposed to the fluid, the resistance imparted to the rotatable impeller can be varied. Users of the fluid resistance unit can thereby adjust the resistance to exercise at varying levels of difficulty. Users can vary the resistance of a fluid resistance unit either continuously or in discrete steps. The adjustment of resistance can be accomplished easily by changing an external lever. A fixed fluid resistance unit can have the amount of its resistance preset at a factory, by simply inserting one of a number of differently spaced barrier plates. The fluid resistance unit can offer progressive resistance to progressively challenge the user. The fluid resistance unit is modular and quiet, and relatively inexpensive to produce.
These and other features and advantages of the present invention will become more apparent from the following description, drawings, and claims.